Help! Brakes wont build pressure... they did before I replaced the lines?

Just replaced the front rubber brake lines on my 58 Buick Super 2 door. Had pressure... now mush pedal forever. We were bleeding the brakes for like 10 minutes solid. Very minor pressure, had fluid at the end of the line. I know sometimes it take a while to push all lost fluid back to the ends of the line. What do yall think the max time limit of bleeding the brakes would be. I'm probably not being patient enough and the wifes leg is getting tired of pumping the brake.